vinoman wrote:I've just installed Mint 13 KDE and wanted to know which driver should I install for a nvidia 8400 gs?

The recommended one from the Additional Drivers icon. It's very easy to do. Go to your start button and enter the System icon. You'll see the Additional Drivers icon right there. Click on it and do what it says.

Or you could also do this:

How To Get & Install Nvidia 302.17 Driver for Mint 13

If you have Ubuntu 12.04 or Linux Mint 13 installed and you want the latest Nvidia 302.17 installed, go to the URL below. I have Mint 13 KDE and this driver works better than the 295.49 that was the default driver in my fresh installation.

vinoman wrote:Thanks, I installed the Nvidia 302.17 driver and after reboot all looks well, though I don't see much difference from the generic drivers from the initial install of Mint 13 KDE. But it looks good.

You're welcome! I was getting a bunch of artifacts on my screen after playing Open Arena and other OpenGL 3D games. It required a reboot to get rid of them. Now it doesn't happen anymore!!